The C.D.C. developed a diagnostic test and distributed testing kits to local health departments around the country.
Prior to arriving at UC Davis Medical Center, the patient was treated at NorthBay VacaValley Hospital in Vacaville, California, according to The Washington Post.
"Whatever happens we're totally prepared", Trump said Wednesday evening, adding later: "There's a chance it could get worse; there's a chance it could get fairly substantially worse, but nothing's inevitable".
Medical staff treating patients infected by the COVID-19 coronavirus at a hospital in Wuhan, China on February 24, 2020.
The U.S. has struggled to develop an accurate test that can be more widely distributed to labs, while others believe the CDC's guidelines for who needs to be tested should be expanded.
The state does not have its own test kits to detect the disease and were not expecting to receive them until mid-March, but a health department spokeswoman said the department may receive the kits as early as next week.
At this time, the CDC says on its website, the virus is "NOT now spreading in the community in the United States".
Newsom said the state expected that the virus would transmit within the community. The total number of cases in the U.S.is 60, according to data from Johns Hopkins University. The students, one from American River College and the other from Cosumnes River College, are medical professionals, and were exposed to the individual off campus before the person tested positive.
"We have to be alert to the possibility of a pandemic", director of the Food and Drug Administration's Center for Biologics Evaluation and Research Peter Marks said in an interview.
"This case was detected through the USA public health system - picked up by astute clinicians", the CDC said in a brief statement about the new patient. The agency said it has not yet ruled out that the patient was exposed to a returned traveler who was infected.
Health officials say the patient "had no known exposure to the virus through travel or close contact with a known infected individual".
In the letter, the medical center also asked a small number of employees to stay at home and monitor their temperature.
"I anticipate that now, with concerns from not just Japan and Korea, but other areas, we may start to see more because those make up a much larger portion of people who travel", she said.
"It's not so much a question of if this will happen anymore, but rather more a question of exactly when this will happen", said the CDC's Nancy Messonnier.
The new virus is a member of the coronavirus family that can cause colds or more serious illnesses such as SARS and MERS.
The state health authority also indicated that the risk of coronavirus to the general public remains low at the moment.